This invention relates generally to lamps, and more specifically to vehicle lamps having an array of light emitting-diodes (LEDs) providing the light, and a structure and method of construction that produces a light structure that is relatively unbreakable and water resistant and/or water proof While the invention is described in particular with its application in and to boat or other similar towed trailers, those skilled in the art will recognize the wider applicability of the inventive principles disclosed hereinafter.
One of the problems we have observed with respect to taillights of various boat trailers and other towed trailers for example, and with respect to vehicle lights in general, is the fact that the lights often become damaged. That is, it is not uncommon for a person who does not routinely tow a boat trailer, to experience problems in backing the boat trailer, for example. Often in backing, the taillight of the trailer becomes damaged. Likewise, boat trailers often are backed into water in order to load or unload a boat to be carried by the trailer. Because prior art light assemblies are not waterproof, water entering the light assembly can and often does damage the electrical capabilities of the light. We have developed a relatively low-cost, water proof/resistant and relatively unbreakable back up and/or taillight and/or turning light, for example, that has wide application for vehicles, both driven and towed. In particular, we have found that a lamp assembly can be molded completely from a suitable cellulosic, copolymer, polycarbonate, or acrylic plastic, and inserted in place of conventional taillights on trailers and vehicles, for example. Preferably, we employ light emitting diodes (LEDs) as the source of illumination for the light structure. The LEDs are mounted to a circuit card or board (i.e. printed circuit board) in any predetermined arrangement. The board and associated LEDs then are completely encapsulated or immersed in the material to form a solid, effectively one-piece device during the manufacturing process.
While other lamp assemblies have employed LEDs in the past, the products of which we are aware did not provide a light structure that is relatively unbreakable alone or water proof/resistance in combination with the structure's other features. For purposes of this specification, relatively unbreakable means unbreakable in the environment of the lamp assembly's intended use during expected or normal operating conditions. For example, we have found that TENITE® available from Eastman Chemical Company is an acceptable material for the lamp assembly of the present invention where the lamp assembly is intended for use in boat trailers. While the material mix employed for injunction molding may vary for the application illustratively described herein, we believe that the material preferably should have an impact resistance of 4.8 ft-lbs. per inch (ten percent (10%) plasticizer formulation). In boat trailer applications, the material thickness may approach one half inch or more, for example, a thickness for which we were unable to find actual manufacturer's data. We have tested other polycarbonate material in prototype assemblies that has sustained 30 ft. lbs. force on the light assembly without damage (tested by dropping a five pound weight from a height of six feet). As indicated above, the preferred material for any particular application is one that does not suffer damage in its intended application during normal or intended operation of that application.
Among the devices of which we are aware that employ LEDs is one described in U.S. Pat. No. 5,632,551 ('551). While employing LEDs generically, the '551 patent describes the use of a conventional lens and an associated metal housing. While recognizing that breakage is a problem, the '551 patent attempts to solve the problem by recessing the lens member within the housing. While the invention described in the '551 may function well in some circumstances, it does not provide the simplified solid structure, water proof/resistant construction and true non-breakable design for light assemblies available with our invention.